"Masters and Johnson’s major conclusion was that there was only one female orgasm and that it originated in the clitoris regardless of where it was felt. This was in spite of their description of the vaginal response to erotic stimulation, explained here by the Breechers: ‘’The vagina too, responds. It can be thought of as a cylinder or ‘barrel’, which remains in a collapsed state in the absence of erotic stimulation. The Masters-Johnson studies have established that the outer third of this barrel reacts in one way and the inner two-thirds in a very different way during the successive phases of sexual response. As sexual tension mounts during the excitement phase… [t]he cervix and the uterus are pulled back and up…producing a ‘tenting’ of the vaginal walls surrounding the cervix. The net result of these and other changes is a dramatic ‘ballooning’ of the inner two thirds of the vagina. The diameter at the widest point of the ballooning may be three times the diameter of the erotically unstimulated vagina; and the total length of the vaginal barrel may be increased as much as a full inch.’’ Given this physical response the vagina cannot be described as inactive or even passive. However, Masters, and Johnson assumed this to be the case, and their findings focused on what they called clitorical orgasms. The female research subjects were chosen on the basis of their capacity to produce orgasms in the laboratory while under observation. Regarding these women, Masters and Johnson found that as ‘contrasted with the male’s usual inability to have more than one orgasm in a short period, many females, especially when clitorally stimulated can regularly have five or six full orgasms within a matter of minutes’. In this context, with these female subjects, it was found that the most intense orgasms on a physiological level occurred as a result of masturbation, not while engaging in penile-vaginal intercourse. In response to these findings, Dr Mary Jane Sherfey, an American psychoanalyst, concluded in 1966 that ‘biology gives to women an inordinate sexual drive and capacity which had to be suppressed in the interests of maternal responsibility and male property rights with the rise of modern civilisation’."